Time and room:10:30 h, seminar room IAPAbstract: Within the last decade cavity optomechanical systems have dramatically advanced in the exploration of the quantum nature of mechanical oscillators. Ground state cooling, coherent optical to mechanical state transfer and the preparation of non-classical mechanical states are just a few examples of the progress in the experimental control of these systems. Some of the recent challenges in the field are the exploitation of optomechanical cavities as a storage for quantum information and for quantum operations and the realization of networks and arrays of optomechanical cavities.
One of the platforms that promisingly tackles these problems are optomechanical crystals. Different structures can thereby access a wide range of experimental parameters, still preserving a small footprint due to their on-chip integration. Their challenging fabrication however requires robust designs and/or means to compensate slight structural deviations. After a brief general introduction of optomechanical crystals, this talk will reveal a design for tunable optomechanical nanobeams that can enable phononic networks and a potential solutions for a 2D cavity for low temperature quantum optomechanics.

Time and room: 17:15, lecture hall IAPAbstract: Current challenges of quantum many-body theory include correlated super-conductivity, topological materials, non-equilibrium phenomena, and complexity at surfaces and interfaces. In particular, the physics near interfaces and surfaces has attracted attention, as it can lead to phases of matter that might not be realized in bulk materials. The increase in functionality due to spin-triplet pairing states in devices has led to the new field of superconducting spintronics.
Of particular interest are effects based on the presence of gemetric phases and on topological stability. Whereas the former open new avenues toward spin control, the latter have recently attracted strong interest due to their robustness with respect to surface disorder. Spin triplet pairing states in bulk materials can be realized in superfluid 3He, in some correlated super-conductors, or in non-centrosymmetric superconductors. Spin-orbit locking in non-centrosymmetric materials may lead to topological superconductivity giving rise to topologically protected surface Andreev states.
I will present self-consistent calculations for topological superconductivity in non-centrosymmetric materials, and for superfluid order in 3He in the presence of spin-active surfaces.